Galectin-9 interacts with Vamp-3 to regulate cytokine secretion in dendritic cells

Area of Science:

• Cell Biology
• Immunology
• Molecular Biology

Background:

• Intracellular vesicle transport, mediated by SNARE proteins, is vital for cellular homeostasis.
• Endosomal trafficking to the plasma membrane is critical for cytokine secretion in dendritic cells (DCs) and initiating immune responses.
• The molecular regulators of DC cytokine secretion remain poorly understood.

Purpose of the Study:

• To investigate the intracellular roles of galectin-9 in regulating immune cell homeostasis and vesicle transport.
• To determine galectin-9's function in intracellular cytokine trafficking within primary human dendritic cells.

Main Methods:

• Investigated galectin-9 function in primary human dendritic cells (DCs).
• Utilized immunoprecipitation-mass spectrometry to identify molecular interactions.
• Assessed the impact of galectin-9 depletion on vesicle trafficking and cytokine secretion.

Main Results:

• Galectin-9 is essential for intracellular cytokine trafficking to the cell surface in DCs.
• Depletion of galectin-9 leads to accumulation and lysosomal degradation of cytokine-containing vesicles in the Golgi complex.
• Galectin-9 interacts with Vamp-3 and is required for rerouting Vamp-3-containing endosomes upon DC activation.

Conclusions:

• Galectin-9 is a necessary mechanistic component for intracellular trafficking, specifically for cytokine transport in DCs.
• This finding impacts the general understanding of vesicle transport mechanisms.
• Identifies novel roles for galectins in governing cell function and immune responses.